Longitudinal Study of Cognitive Decline before and after the COVID-19 Pandemic: Evidence from the PA-COVID Survey.

introductionEven though several studies reported good resilience capacities in older adults in the first period of the coronavirus disease 2019 (COVID-19) pandemic, in the long run, social isolation induced by the protective measures adopted by most countries may negatively impact cognitive functioning. Taking the advantage of measures collected up to 15 years before the pandemic in participants followed up in epidemiological studies, we compared cognitive decline before and after the start of the pandemic.

methodsPA-COVID is a phone survey designed in the framework of ongoing population-based studies (PAQUID, 3-City, Approche Multidisciplinaire Intégrée cohorts). Data on social functioning and mental health were collected in participants aged 80 years and older during the pandemic. Prior to the pandemic, the participants followed up in the prospective studies completed the Mini-Mental State Examination. During the PA-COVID survey, they underwent the Telephone Interview for Cognitive Status. A score was computed with the 11 items shared by the 2 tests. Our analysis was carried out in the participants for whom a cognitive measure was available up to 15 years before the pandemic and during the pandemic (n = 263).

resultsCompared to the slow decline of the cognitive subscore observed during the 15 years preceding the pandemic, mixed models showed an acceleration of decline after the start of the pandemic (β = -0.289, p value <0.001).

conclusionsWith a design allowing comparing cognitive trajectory before and after the pandemic, this is the first study reporting an accelerated decline in older adults. Future COVID research in older adults will need to pay special attention to cognitive outcomes.